インドールと非活性化オレフィンとのプラチナ触媒による分子内アルキル化
Cong Liu1, Xiaoqing Han, Xiang Wang
1P. M. Gross Chemical Laboratory, Duke University, Durham, North Carolina 27708-0346, USA.
Journal of the American Chemical Society
|March 25, 2004
まとめ
プラチナ触媒は,2-アルケニルインドールからカルバゾール誘導体の効率的な合成を可能にします. この方法は,様々な置換を許容し,保護されていないインドルおよび関連するヘテロサイクルに適用できる多用途です.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- ヘテロサイクル化学 ヘテロサイクル化学
背景:
- インドール誘導体は,医薬品化学における重要な支架である.
- 複雑なインドル基ヘテロサイクルのための効率的な合成経路は,非常に求められています.
- プラチナ触媒は,C-C結合形成のためのユニークな反応性を提供します.
研究 の 目的:
- 2-アルケニルインドールのための新しいプラチナ触媒サイクリング方法の開発.
- この触媒システムの範囲と限界を探求する.
- 反応メカニズムを解明するために.
主な方法:
- 1-メチル-2-(4-ペンテニル) インドールとプラチナ(II) クロリド (PtCl2) 触媒の反応.
- 微量塩酸 (HCl) の溶媒としてダイオキサンを使用する.
- プラチナ複合体のオレフィンに対する核愛性の攻撃を含むメカニズム研究.
主要な成果:
- 4,9-ジメチル-2,3,4,9-テトラヒドロ-1H-カルバゾールの高収量 (92%) 隔離.
- ペンテニル鎖における置換物の許容度.
- テトラヒドロベータカルボリノンの合成が成功しました.
- 独占的な6エンドトリガー地域選択性は,2-...3-ブテニル) インドールで観察されました.
- 保護されていないインドールに対する適用性の実証.
結論:
- プラチナ触媒によるサイクリングは,代用されたカルバゾールおよび関連するヘテロサイクルのための効率的な経路を提供します.
- このプロトコルは頑丈で,多用途で,インドールが協調したオレフィンに核愛的に攻撃することで進行します.
- この方法論は,複雑な窒素を含むヘテロサイクルにアクセスするための合成ツールキットを拡張します.
関連する概念動画
Acid Halides to Carboxylic Acids: Hydrolysis
Hydrolysis of acid halides is a nucleophilic acyl substitution reaction in which acid halides react with water to give carboxylic acids. The reaction occurs readily and does not require acid or a base catalyst.
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
Nitriles to Ketones: Grignard Reaction
Organomagnesium halides, commonly known as Grignard reagents, convert nitriles to ketones and proceed through a nucleophilic acyl substitution. Nitriles react with a Grignard reagent, followed by an aqueous acid, to yield ketones. The reaction introduces a new carbon–carbon bond. The alkyl–magnesium bond in the Grignard reagent is highly polar, so the alkyl carbon develops a carbanionic character and acts as a nucleophile.
The mechanism begins with a nucleophilic attack by the Grignard reagent...
The mechanism begins with a nucleophilic attack by the Grignard reagent...
Amines to Amides: Acylation of Amines
Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
The pinacol and McMurry reactions involve the reductive coupling of ketones or aldehydes. Similarly, the bimolecular reductive coupling of two ester molecules in the presence of sodium metal in an aprotic solvent yields an α-hydroxy ketone product. The α-hydroxy ketone is also called acyloin, so the reaction is referred to as ‘acyloin condensation.’
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Acetoacetic ester synthesis is a method to obtain ketones from alkyl halides and β-keto esters. The reaction occurs in the presence of an alkoxide base that abstracts the acidic proton of the β-keto esters. The step results in an enolate ion which is doubly stabilized. The enolate then reacts with an alkyl halide via the SN2 process to produce an alkylated ester intermediate with a new C–C bond. The hydrolysis of the intermediate, followed by acidification, results in an alkylated β-keto acid.
Reactions of Carboxylic Acids: Introduction
Carboxylic acids possess an acidic –COOH functional group. The acidity can be attributed to the resonance stabilization of their conjugate base, wherein the negative charge is delocalized over both oxygen atoms.


